A phase shifter is connected to an antenna device, e.g. radiation device, and changes a phase of a signal transmitted to the antenna device. In addition, the phase shifter has a structure as shown in below FIG. 1.
FIG. 1 is a top view illustrating a common phase shifter. FIG. 2 is a view illustrating schematically a lower part of the phase shifter in FIG. 1.
In FIG. 1, the phase shifter includes a dielectric substrate 100, a first line 102, a second line 104, an input line 106, an output line 108, a rotation axis member 110, an arm member 112 and a guide member 114.
The dielectric substrate 100 is made up of dielectric material having certain dielectric constant. Here, a ground plate (not shown) is formed on a lower surface of the dielectric substrate 100.
The first line 102 is formed on the dielectric substrate 100 as a conductor. Here, ends of the first line 102 are connected to a first radiation device and a second radiation device.
The second line 104 is formed on the dielectric substrate 100 as a conductor, wherein ends of the second line 104 are connected to a third radiation device and a fourth radiation device.
The input line 106 receives a RF signal as a conductor.
The received RF signal is outputted to a fifth radiation device through a first dielectric substrate area located below the output line 108 of the dielectric substrate 100, or is coupled at the rotation axis member 110 and then is transmitted through a second dielectric substrate area located below the aim member 112 of the dielectric substrate 100. Here, a third line (not shown) as a conductor is formed on a lower surface of the arm member 112. Subsequently, the RF signal transmitted through the second dielectric substrate area is coupled between end of the third line and the lines 102 and 104, and then is transmitted to corresponding radiation devices.
The output line 108 as a conductor outputs the RF signal to the first radiation device without changing phase of the RF signal considering beam characteristic of an array antenna having the radiation devices.
The rotation axis member 110 is combined with a gear wheel 200 as shown in FIG. 2, and is connected to the arm member 112 and the guide member 114 as shown in FIG. 1. Here, the gear wheel 200 rotates in response to rotation of the gear worm 202, and so a rotary power in accordance with the rotating is provided to the arm member 112 through the guide member 114. That is, the phase shifter rotates the gear worm 202 in a forward direction or a reverse direction for the purpose of changing the phase of the signals transmitted to the radiation devices, thereby rotating the arm member 112.
Hereinafter, combination relation of elements in the phase shifter will be described in detail.
FIG. 3 is a sectional view illustrating the phase shifter in FIG. 1.
In FIG. 3, the rotation axis member 110 is combined with the gear wheel 200, and is connected to the arm member 112 and the guide member 114 through the dielectric substrate 100.
The guide member 114 is connected to the rotation axis member 110, rotates in response to rotation of the rotation axis member 110, and includes a guide base member 114A, a side member 114B, a supporting member 114C and a projection member 114D.
The guide base member 114A is located on an upper surface of the atm member 112.
The supporting member 114C is longitudinal-extended in a direction of the rotation axis member 110 from the side member 114B, is located on a lower surface of the dielectric substrate 100, and is supported by the dielectric substrate 100.
The projection member 114D is projected from the guide base member 114A, and is inserted into a part of the arm member 112 as shown in FIG. 3. As a result, the arm member 112 is fixed to the guide member 114, thereby rotated with the guide member 114 when the rotation axis member 110 is rotated.
In brief, the phase shifter rotates the guide member 114 as much as desired length by rotating the gear worm 202 and the gear wheel 200 so as to control phase change of the signals. As a result, the arm member 112 connected to the guide member 114 is rotated with desired phase change.
However, in case that the gear worm 202 is rotated in a forward direction and then rotated in a reverse direction in the phase shifter, loss of the rotary power from the gear worm 202 and the gear wheel 200 may occur until the rotary power is provided to the arm member 112 due to friction between the gear worm 202 and the gear wheel 200 and loss in a process of delivering the power, etc.